Dermatitis encompasses a number of conditions characterized by reddish skin lesions that can develop into scaly, thickened plaques. These lesions can arise from any of several primary causes, including contact with allergens, ultraviolet light or chemicals, systemically administered drugs, or localized trauma (irritation). The causes of certain forms of dermatitis are unknown.
Eczematous dermatitis refers to a group of conditions characterized in the initial stages by edematous, oozing plaques that often contain blisters. These lesions are prone to bacterial infection. Fluid leaks into the intercellular spaces in the epidermis, giving it a spongy appearance. Over time, oozing diminishes, and the lesions become scaly as the epidermis thickens (epidermal hyperplasia).
Of particular concern are chronic forms of dermatitis, including psoriasis and the chronic stages of eczematous dermatitis. Psoriasis is characterized by round, thick, dry, reddish patches covered with silvery scales. Psoriasis may be localized or generalized, and in the latter case may become life-threatening. Psoriatic lesions show marked epidermal hyperplasia and hyperproliferation of keratinocytes. The etiology of psoriasis is believed to include hereditary and autoimmune components. Chronic lesions of eczematous dermatitis are clinically and histologically similar to psoriatic plaques.
Cellular proliferation (e.g. proliferation of keratinocytes) is regulated in part by intracellular calcium levels. Changes in intracellular calcium concentrations influence the phosphorylation of proteins, thus influencing proliferation and other cellular processes. One of the molecules that mediates the effect of intracellular calcium levels on protein phosphorylation is calmodulin, a protein co-factor for protein kinase C.
Psoriasis is treated by the application of corticosteroids, coal tar ointments, or anthralin. These treatments are only partially effective and may merely contain, not reverse, the disease. Anthralin may cause irritation, and its safety in children and pregnant women has not been established. Corticosteroids have a number of undesirable side effects, including edema and mineral imbalances. Non-steroidal anti-inflammatory agents are generally not effective.
Certain substituted 2,3-diaryl-1-benzopyrans have been shown to have antiestrogenic activity with little or no estrogenicity, and have been proposed for use in the treatment of breast cancer. See Kapil et al., U.S. Pat. No. 5,254,568; Saeed et al., J. Med. Chem. 33: 3210-3216, 1990; Sharma et al., J. Med. Chem. 33: 3222-3229, 1990; and Sharma et al., J. Med. Chem. 33: 3216-3222, 1990. These compounds have not previously been shown to have anti-inflammatory properties or to be effective against dermatitis.
There remains a need in the art for treatments for dermatitis that are effective and lack serious side effects. The present invention addresses this need and provides other, related advantages.